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Wednesday, May 29, 2013

The whole programming procedure of transfering a sketch from Arduino to an ATtiny85, can be shown here on a short video I made.
The full guide with all the nessecary steps can be found in my previous post.

Wednesday, May 22, 2013

An RGB Led has two variations. The Common Anode and the Common Cathode. Both of them have 4 pins, 3 of them are the three colors Red, Green and Blue and 1 is the common pin.

Typical 4 pins RGB Led

RGB Pin-Out Schematic

As shown in the pin-out diagram of the Common Anode (CA) RGB Led, Vcc input goes to pin 1 and the rest are: Red-2, Green-3 and Blue-4. When these three goes LOW, the colors lights up. With the proper combinations we can simulate all the colors on the RGB scale. Furthermore by using the PWM function of Arduino we can adjust the level of each color and create a fading sequence.

Monday, May 20, 2013

Arduino projects are very popular but also big and expensive. There are many times that we don’t need so many input or output pins. As a matter of fact, most projects could be accomplished with only 2 or 3 inputs and outputs. Besides the size, using one Arduino board for each small project can be costly.

Atmel's tiny... ATtiny85

So the solution is given (again) by Atmel with the ATtiny microcontrollers. Especially the ATtiny85 chip, which has 8 Kb flash memory, 6 input/output pins, low power supply at 1.8-5.5V, small 8-pin packaging and costs only 2-3$.

ATtinyShield - easy Arduino programming

It is very easy to program the ATtiny85 using our own Arduino board based on the tutorial Arduino-based ATtiny programming(http://hlt.media.mit.edu/?p=1695) published by MIT’s High-Low Tech research group. So we have to connect the ATtiny85 (pins 1, 5, 6, 7) with 4 digital outputs of our Arduino (pins 10, 11, 12, 13), give 5V and Ground to pins 8 and 4 of the microcontroller and finally place a 10uF Electrolytic Capacitor between the Reset and Ground of the Arduino.

In my project I have added an indicator LED on pin 9 of the Arduino that shows that the programmer is running properly and a reset tact switch for the ATtiny85.

So by creating a small shield with all these connections, it’s easy to plug it on our Arduino and worry only about the programming stuff. This is what ATtinyShield is doing for us.

If you want to buy this shield check, my EBay listing:

The shield with printed and
already etched PCB with color silkscreen on it, and of course the
components soldered on it. It will be fully functionable ready to
program.

An Attiny85 20PU chip for your first experiments.

A detailed printed (and pdf) guide (in color) for the connections and the whole programming procedure.

The
RGB-Tiny board, a small PCB with RGB Led, controlled by an ATtiny85
for your first experiments. With code provided you will be able to fade
the Led to all colours or any other programming you want.